> The Bill additionally proposes to remove the requirement to number all candidates on the ballot paper. This is a little more contentious as it introduces new electoral strategies and can impact both positively and negatively on voting outcomes.<p>I know that it may be impossible to have a voting system which is both strategy-proof and has other desirable properties, but I don't think this limitation requires that the available strategy actually be exploitable (or even findable) in practice by actual voters.<p>Unfortunately it seems that the mentioned Australian system (despite all its other benefits over FPTP) has exploitable strategies both with and without the complete ordering requirement, which gives a malicious administration one "bit" of control over the algorithm.<p>Even if they can't predict the magnitude of the effect, they could be tempted to flip that bit based on the <i>direction</i> of the expected change. From the defender's perspective, the fact that the magnitude is not predictable should be even more cause for concern.